Dry-spinning of continuous cellulose fibers using only nanofibers from a bio-residue
2014 (English)Conference paper, Presentation (Refereed)
IntroductionFibers are widely used in polymer composites and the highest mechanical properties are achieved when fibers are continuous and aligned in the direction of the applied load. For this reason continuous glass fiber composites are commonly used in structural applications. These glass fibers have high stiffness (70 GPa) and strength (3400 MPa) but have a high environmental impact. An alternative is to use natural fibers since they have a low environmental impact and good mechanical properties, e.g. flax fibers have a stiffness of 70 GPa and strength of 900 MPa. However, natural fibers are short and discontinuous and conventional spinning results in highly twisted yarns, which negatively impact the mechanical properties of the composites1. One solution to overcome these limitations is to prepare continuous biobased man-made fibers from cellulose. Thermoplastic cellulose-based biopolymers such as cellulose acetate butyrate (CAB) can be melt-spun but the low mechanical properties of these fibers make them unsuitable for use in structural composites. Nanoreinforcing as well as aligning the polymer chains and nanoreinforcements were investigated but the improvements in the final properties of CAB nanocomposites fibers were still far below the desired values2,3. Regenerated cellulosic fibers are another type of continuous cellulosic man-made fibers but again their mechanical properties are lower than that of native cellulose, e.g. Lyocell has a stiffness of 16 GPa and strength of 660 MPa. Therefore, of interest is the manufacture of aligned continuous native cellulose fibers. Cellulosic fibers have been prepared by simply wet spinning tempo-mediated oxidized cellulose nanofibers (CNF) through a syringe into an organic liquid 4, 5. Though, high mechanical properties of the fibers have been reported, tempo-mediated oxidation and using solvents for precipitation does not make the process economical. In the current study, low-cost continuous cellulose fibers from a bio-residue CNF without additional chemicals and solvents were prepared. The effect of spinning rates as well as the effect of CNF concentration on the mechanical properties of the fibers was investigated.ExperimentalCellulose nanofibers were extracted from bleached banana rachis waste using ultra-fine grinder (Masuko Sangyo Co., Saitama, Japan). The bleached fibers were supplied by ECLIPSE project. A suspension of 2wt% was concentrated to different concentrations (8, 10 and 12 wt%) using centrifugation. Dry spinning of the fibers were carried out at three spinning rates (72, 144 and 216 mm/s) using a Rheo-tester 1000 (Göttfert, Buchen, Germany) equipped with a 1 mm single hole die with length of 20 mm. The spun fibers were then collected and mounted on glass sheets before being dried at room temperature followed by oven drying to remove any remaining moisture (Fig. 1). For comparison a nanopaper from the CNF was also made by vacuum filtration and drying.References1. Goutianos et al.: Appl Compos Mater, 2006, 13 199-215.2. Hooshmand et al.: Plast Rubber Compos, 2014, 43 (1) 15-24.3. Hooshmand et al.: Cellulose, 2014 accepted.4. Walter et al.: Adv Mater, 2011, 23 2924-2928.5. Iwamoto et al.: Biomacromolecules, 2011, 12 831-836.AcknowledgementsThe authors thank Bio4Energy for financial support of this project as well as ECLIPSE project (grant agreement nº: 280786) for the banana nanofibers.
Place, publisher, year, edition, pages
Research subject Wood and Bionanocomposites
IdentifiersURN: urn:nbn:se:ltu:diva-38502Local ID: cecbc810-d045-43f5-ae25-ee477da73702OAI: oai:DiVA.org:ltu-38502DiVA: diva2:1012003
Workshop Green Chemistry and Nanotechnologies in Polymer Chemistry : ECLIPSE Workshop, BIOPURFIL Workshop 09/07/2014 - 11/09/2014
Godkänd; 2014; 20140916 (salhoo)2016-10-032016-10-03Bibliographically approved